<template>
  <section class="todoapp">
    <!-- header -->
    <header class="header">
      <input class="new-todo" autocomplete="off" placeholder="Todo List" @keyup.enter="addTodo">
    </header>
    <!-- main section -->
    <section v-show="todos.length" class="main">
      <input id="toggle-all" :checked="allChecked" class="toggle-all" type="checkbox" @change="toggleAll({ done: !allChecked })">
      <label for="toggle-all"/>
      <ul class="todo-list">
        <todo
          v-for="(todo, index) in filteredTodos"
          :key="index"
          :todo="todo"
          @toggleTodo="toggleTodo"
          @editTodo="editTodo"
          @deleteTodo="deleteTodo"/>
      </ul>
    </section>
    <!-- footer -->
    <footer v-show="todos.length" class="footer">
      <span class="todo-count">
        <strong>{{ remaining }}</strong>
        {{ remaining | pluralize('item') }} left
      </span>
      <ul class="filters">
        <li v-for="(val, key) in filters" :key="key">
          <a :class="{ selected: visibility === key }" @click.prevent="visibility = key">{{ key | capitalize }}</a>
        </li>
      </ul>
      <!-- <button class="clear-completed" v-show="todos.length > remaining" @click="clearCompleted">
        Clear completed
      </button> -->
    </footer>
  </section>
</template>

<script>
  import Todo from './Todo.vue'

  const STORAGE_KEY = 'todos'
  const filters = {
    all: todos => todos,
    active: todos => todos.filter(todo => !todo.done),
    completed: todos => todos.filter(todo => todo.done)
  }
  const defalutList = [
    { text: 'star this repository', done: false },
    { text: 'fork this repository', done: false },
    { text: 'follow author', done: false },
    { text: 'vue-element-admin', done: true },
    { text: 'vue', done: true },
    { text: 'element-ui', done: true },
    { text: 'axios', done: true },
    { text: 'webpack', done: true }
  ]
  export default {
    components: { Todo },
    filters: {
      pluralize: (n, w) => n === 1 ? w : w + 's',
      capitalize: s => s.charAt(0).toUpperCase() + s.slice(1)
    },
    data() {
      return {
        visibility: 'all',
        filters,
        // todos: JSON.parse(window.localStorage.getItem(STORAGE_KEY)) || defalutList
        todos: defalutList
      }
    },
    computed: {
      allChecked() {
        return this.todos.every(todo => todo.done)
      },
      filteredTodos() {
        return filters[this.visibility](this.todos)
      },
      remaining() {
        return this.todos.filter(todo => !todo.done).length
      }
    },
    methods: {
      setLocalStorage() {
        window.localStorage.setItem(STORAGE_KEY, JSON.stringify(this.todos))
      },
      addTodo(e) {
        const text = e.target.value
        if (text.trim()) {
          this.todos.push({
            text,
            done: false
          })
          this.setLocalStorage()
        }
        e.target.value = ''
      },
      toggleTodo(val) {
        val.done = !val.done
        this.setLocalStorage()
      },
      deleteTodo(todo) {
        this.todos.splice(this.todos.indexOf(todo), 1)
        this.setLocalStorage()
      },
      editTodo({ todo, value }) {
        todo.text = value
        this.setLocalStorage()
      },
      clearCompleted() {
        this.todos = this.todos.filter(todo => !todo.done)
        this.setLocalStorage()
      },
      toggleAll({ done }) {
        this.todos.forEach(todo => {
          todo.done = done
          this.setLocalStorage()
        })
      }
    }
  }
</script>

<style lang="scss">
  @import './index.scss';
</style>
